I'd need a physiologist to confirm, but my understanding is as follows:
If badzilla is affecting Froome's performance, you might think, logically, that as soon as it's cured, he can ride stronger, but I do not think that is necessarily the case.
Let's look at a doping example: testosterone.
Just taking testosterone alone will not make you stronger. You have to train to get stronger. The process is:
1. overload
2. recover
3. supercompensation --> getting fitter and stronger
If you only train as hard and as often as you did before taking testosterone, you're not going to improve any quicker, as the overload will be the same. Yes, you have better recovery, but you didn't stress your body more, so the greater recovery is not going to help any. With testosterone you recover quicker, so you can train as hard, but more often. ie the recovery has increased, therefore you can increase the overload, leading to a greater supercompensation. You get fitter and stronger, more quickly.
Now Froome is anti-doped with Bilharzia. Not only is his ability to overload reduced, but so too, apparently, is his recovery. His performances pre-Vuelta 2011, various interviews and biography all confirm his inability to recover.
If Froome can only overload like a Cat 1 rider, then he will only ride like a Cat 1 rider. He spends most of his pro life riding like a Cat 1 rider - not a top level pro.
As soon as the Bilharzia is cured, he can now
1. overload his body like a protour (PT) rider
2. recover like a PT rider
3. have the supercompensation of a PT rider
but this process takes time. He hasn't been overloading like a PT rider at all, nor recovering like one, since he turned pro.
It should take some time - up to a year or more - once the Bilharzia has been cured, to reach his "genetic potential".
You'd expect to see some improvement, over time, but in 7 weeks he went from Cat 1 domestique to world beater.